CN1836415A - Encryption method and decoding method for a digital transmission system - Google Patents
Encryption method and decoding method for a digital transmission system Download PDFInfo
- Publication number
- CN1836415A CN1836415A CNA2004800232291A CN200480023229A CN1836415A CN 1836415 A CN1836415 A CN 1836415A CN A2004800232291 A CNA2004800232291 A CN A2004800232291A CN 200480023229 A CN200480023229 A CN 200480023229A CN 1836415 A CN1836415 A CN 1836415A
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- code
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- training sequence
- digital data
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2602—Signal structure
- H04L27/261—Details of reference signals
- H04L27/2613—Structure of the reference signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
- H04L9/06—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols the encryption apparatus using shift registers or memories for block-wise or stream coding, e.g. DES systems or RC4; Hash functions; Pseudorandom sequence generators
- H04L9/065—Encryption by serially and continuously modifying data stream elements, e.g. stream cipher systems, RC4, SEAL or A5/3
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- Computer Networks & Wireless Communication (AREA)
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- Computer Security & Cryptography (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
An encryption method and decoding method for a digital transmission system, in which the digital data stream comprises an alternating sequence of training sequences and data symbols, and the training sequences are dynamically coded. At the receiving end, a decoding code (Vn) is generated by a code generator as a function of an encryption key (200). This decoding code is sent to a correlator, where it is mixed with the encryption code Vn extracted from the digital data stream. The correlator generates a correcting variable to compensate the offset in respect of time or frequency between the sender and receiver. Encryption is achieved through the alteration of the code used during the transmission.
Description
Technical field
The present invention relates to be used for the encryption method and the coding/decoding method of digital transmission system, digital transmission system comprises transmitter and receiver, and transmission wherein can be wireless or wired according to expectation.In digital communication system, the sign synchronization that receiver must arrive with the form with modulation is so that realize best demodulation.Frequency Synchronization for multicarrier modulation system, especially be important for OFMD (OFDM) multicarrier method.Timing error or frequency departure (frequency shift (FS)) will be introduced inter-carrier interference (ICI) and intersymbol interference (ISI) for this transmission system, thereby the demodulation of symbol no longer may.
Background technology
Known method for synchronous is " data-aided synchronous " method.The principle of this method for synchronous is to use training sequence or the pilot subcarrier with reference symbol, and they are stored in transmitter and receiver within the two.At first, from the input signal of scanning, extract training sequence and be sent to a correlator, secondly, call the reference sequences that is stored in the receiver and also be sent to said correlator.According to the maximum that correlator finds, during the time of input signal grating inquiry (time-rasterized interrogation), the gated sweep device is so that transmitter and receiver are synchronous as much as possible.The correlation of the training sequence that receives and the reference sequences of storage can be estimated symbol timing and frequency shift (FS).
Fig. 1 is used to illustrate prior art, schematically represents a digital data stream r, and digital data stream r comprises an alternate sequence from the reference symbol of training sequence c and data symbol s.What training sequence c showed is reference symbol, and reference symbol is stored in transmitter and receiver among these two, for example can be the continuous bit sequence of constant length.The code that random generator produces is generally used for training sequence.
Fig. 2 of explanation prior art a) and 2b) in represent synchronous basic skills.Fig. 2 a) represents to have the insertion of the data symbol of constant code c.The digital data stream r that will send derives from this.
At Fig. 2 b) in, utilize vector C to extract training sequence from the data flow r that receives.Training sequence and storage or the reference sequences c that is created in the receiver are compared.When finding a maximum, the control of symbol clock and receiver symbol timing just with the said control of transmitter and coupling regularly, but and thus maximum possible compensated frequency shift (FS).Reference sequences or training sequence comprise a vector, and this vector has the reference symbol number P.With following equation (1) this vector is described here:
c＝[c
0?c
1?C?c
(p-1)]
T (1)
Can use this method in the two in the symbol time-domain and the frequency domain of frequence estimation regularly.Said method is described as a typical example of the synchronous symbol that uses the data support here.
In the duration that connects, this vector C remains unchanged.This will make unwarranted third party for example come at the synchronous equipment of current connection by testing out different codes.So unwarranted third party might use adequate measures to intercept and capture (intercept) this connection.
Summary of the invention
Therefore, an object of the present invention is provides an encryption method for the digital transmission system of identical universal class, is used to increase the fail safe that prevents intercepted data stream.Another object of the present invention is to provide a kind of method for the decoding according to the digital data stream of cipher mode transmission.A further object of the invention provides the equipment that is used to implement this type method.Next purpose of the present invention provides and has improved a kind of digital transmission system that prevents the fail safe of intercepting and capturing.
With regard to the encryption method that is used for digital transmission system, said purpose realizes by a kind of method, digital data stream wherein comprises an alternate sequence of training sequence or pilot frequency carrier wave (following is referred to as training sequence) and data symbol, send said training sequence according to coding form, so that the coding of training sequence utilizes dynamic encryption code to realize.At this on the one hand, saidly mean dynamically that the training sequence that the vector by specific length forms has different contents in the process of time.In other words, during the transmission, the content of training sequence is to change, and consequently, has improved and prevents from the fail safe of intercepting and capturing to have reached an encryption level.
According to one embodiment of the present of invention, produce dynamic encryption code by a random generator.
An alternative embodiment of the invention is for method for scrambling use each continuous element of determining group from encrypted code.The group that this of encrypted code determined for example can be produced in advance by random generator, has perhaps programmed when producing corresponding equipment.
According to an alternative embodiment of the invention, dynamically training sequence is each element from one group of training sequence, and applies continuously.Here, this group training sequence can:
-send to receiver from transmitter, and put into (centre) memory by receiver; Perhaps
-produce by receiver according to the figure of determining, before intermediate storage subsequently, produce, perhaps just produce simultaneously.
According to another embodiment, this organizes dynamic training sequence and implements according to circulation form, that is, and and from beginning to the end and then from beginning.This just can guarantee that each single training sequence only is used for the specific time, and, under the situation of long Digital Transmission of moment more specific,, do not reach half inactive state of this coding as the result of last element of the training sequence of use continuously than this.For these embodiment, when sending end and receiving end, to change training sequence simultaneously.The moment that training sequence changes all is known for transmitter and receiver, because agree between transmitter and receiver during connecting foundation.
With regard to coding/decoding method, the objective of the invention is to realize by a kind of method, said method is used for the digital data stream by scanner foundation, an and alternate sequence that comprises training sequence and data symbol, training sequence is wherein encoded, and after the numerical data scan flow that receives, from said digital data stream, extract and send it to a correlator, wherein the decoding code of receiving terminal also sends to correlator, correlator is sought a maximum according to these two signals, this maximum is as the time of scanner and the correcting variable of frequency correction, and the code of wherein decoding is dynamic, code generator produces the dynamic decoder code, as the function of encryption key.Because decoding code time to time change, that is, it is dynamic, prevents the fail safe of intercepting and capturing so improved.Code generator produces the dynamic decoder code, and as the function of the content of encryption key, the content of encryption key just is sent out in the beginning of transfer of data, and comprises the information necessary that produces dynamic code.The metric of the time and frequency shift of result's representative between transmitter and receiver of this correlation.
According to one embodiment of the present of invention, a permutation function has been determined the content of one group of decoding code.A said group comprises a plurality of decoding codes, compiles these decoding codes by permutation function on accurate random basis, and permutation function has wherein been used (pond) decoding code of specified quantity.Because therefore each decoding code in this pond can require for very little comparatively speaking memory space according to different reiteration compilings, has the possible decoding code compiling group of suitable big figure.
According to an alternative embodiment of the invention, coding/decoding method comprises the steps:
Send an encryption key, thus:
Determine a permutation function;
Determine one group of decoding code;
Determine a hop interval;
Wherein: these three steps can be carried out according to any order at last.Permutation function has been determined to extract specific decoding code and it has been stored in one group of order in the decoding code from a pond.The number or the duration of the grouping of hop interval designation data, the variation that after this duration, produces next one decoding code.
According to a modification of the present invention, carry out a replacement process, comprising circulation with following step:
A time interval is set at 1;
Wait for the end of predetermined hop interval;
Spacing value adds 1;
Carry out following comparison: whether currency at interval greater than the sum at the permutation function interior element, and permutation function represents to be used for the position of the dynamic code of decoded digital data flow;
Wherein:, following thing takes place then if result relatively is positive:
The interval is reset to numerical value 1;
Perhaps, if result relatively bears, then:
Make current decoding functions and equate corresponding to decoding code by the code of the position of permutation function regulation.
This permutation function is provided at will use and each decoding code that replaced by different decoding codes subsequently of duration at an interval.
In a word, just can improve and prevent from the fail safe of intercepting and capturing from wherein can realize different encryption levels by changing code in time according to variation of the present invention.Can be individually or use following measure with mutually combining:
1) uses a different set of encrypted code;
2) use a permutation function; And/or
3) use hop interval, hop interval is connected with different length for difference.The measure of implementing is many more, and complexity is high more, so secret grade is high more.By using the various factors of more content, and, can further increase complexity therefore by using bigger variation.
In the physical layer of OSL 7 layer models, use the present invention.
With regard to equipment, the objective of the invention is to realize by a kind of equipment, said equipment is used for the digital data stream of synchronous receiver and reception, wherein: in order to realize from the digital data stream that receives, extracting training sequence, and send it to correlator synchronously, here they are that identifying code mixes with a decoding code, thereby find a maximum, this maximum is used as the correcting variable of scanner, and wherein: synchronizer is equipped with a dynamic code generator.The dynamic code generator alternately produces the decoding code of current needs or produces one group of complete decoding code, and they are stored in the memory.
In an equipment, for example in a mobile phone, dynamically generator can be used for encrypting and being used for decoding at reception period during the transmission.
According to one embodiment of the present of invention, synchronizer is equipped with the device that is used for the storage encryption key, for example RAM (random access memory).
With regard to transmission system, the objective of the invention is to realize that by digital transmission system the synchronous equipment that is used for receiver has the digital data stream of reception that wherein receiver is equipped with:
Be used to extract the device of training sequence;
The device that is used for the correcting variable of definite scanner;
Be used to produce the device of dynamic code.
The correcting variable of scanner is for example determined by an adjuster.Said adjuster influences scanner, so that can reduce timing or frequency shift (FS) between transmitter and the receiver.The device that is used to produce dynamic code for example can be a code generator, and code generator can produce a plurality of decoding codes that are used for each connection according to encryption key.
A kind of application of encryption method and/or coding/decoding method, digital data stream wherein comprises an alternate sequence of training sequence and data symbol, and training sequence (for example electric communication network or WLAN (wireless local area network)) in wired or wireless network is a dynamic coding.
Description of drawings
Example with reference to the embodiment that represents in the accompanying drawings further describes the present invention, but the invention is not restricted to these examples.
Fig. 3 schematically represents to have a digital data stream of the training sequence of dynamic change;
Fig. 4 schematically and be divided into two parts a) and b) expression is used for the flow chart of data flow of the dynamic encryption of synchronous receiver and reception;
Fig. 5 represents the flow chart of coding/decoding method;
Fig. 6 represents a pond being made of each code.
Embodiment
Fig. 3 schematically represents a digital data stream x (t), and digital data stream x (t) comprises the training sequence v of dynamic change
n, v
N+1An alternate sequence with data symbol u.Training sequence v
nOr v
N-1Send with coding form.Because code changes in transmission course, so realized first encryption level.In this connected, coding meaned the identical code of duration use for transmission.Encryption in this connection means at least two the different codes of duration use for transmission.
Embodiment hereto, for the hop interval less than the data symbol duration, different codes is used at least two continuous training sequences, uses v
n, v
N+1Expression.These two code v
n, v
N+1Comprise the reference symbol that is used for synchronous similar number P.Each code v
n... v
N+1The reference symbol of showing similar number P, but reference symbol itself is inequality.Other modification can change the code after the greater number data symbol, perhaps changes the code of preset time after expiring.
Fig. 4 a) is illustrated in mixing of the data symbol u that produces in the transmitter and time dependent encrypted code v (t).The result who mixes is digital data stream x (t).
Fig. 4 b) flow chart of the data flow x (t) of expression synchronous receiver and reception.The scanning of the data flow x (t) that receives is relevant with the time.In order to obtain optimal results, importantly, timing or frequency shift (FS) between the local clock of transmitter and the local clock of receiver are very little.Extracting training sequence v
nAfter, be with training sequence v
nSend to correlator, here training sequence v
nReference signal v with receiver
nCompare.Investigate the maximum of correlated results, this maximum is as the correcting variable of regulating scanner.Here the method for synchronous of Miao Shuing can be described as dynamic approach, is time dependent because encrypt the code of training sequence.The dynamic code generator is created in the analogous training sequence v of receiving terminal according to encryption key
n, i.e. reference signal.Variable (t) clearly illustrates that encrypted code v (t) changes in time, promptly is dynamic.That following footnote n represents is a specific instantaneous encrypted code v
n, encrypted code v
nCan be by the instantaneous encrypted code v of the next one
N+1Replace.
Fig. 5 schematically represents to be used for according to the present invention the method for the digital data stream x (t) of the receiver of synchronous digital transmission system and reception with a flow chart.After step 100 connect to be set up, send an encryption key in step 200, at said step 200 determining with the parameter below any order initialization:
Permutation function F
i210;
One group of decoding figure G
i220;
Hop interval I
Hop230.
Produce encryption key 200 by transmitting element, encryption key 200 comprises the required and synchronous required parameter of data-signal that decoding sends.
Permutation function F
i=p-1, p-2 ... p-M} represents to use from a group encryption figure G
iEach code g
1, g
2... g
HOrder, here, p-1, p-2 ... p-M is an entire data 1,2 arbitrarily ... H.For example, if a specific permutation function F={2, H}, in other words, p-1=2 and p-2=H, and during decoding, at first use encrypted code g
2, use encrypted code g then
HAlso not finishing if connect, then proceed decoding according to circulation form, that is, (is g with p-1 earlier
2), using p-2 then (is g
H).Step 210 for the effective permutation function of current transmission determine can with following described any one replace:
A) send a vector F
i, vector F
iComprise specific constant series p-1, p-2 ... p-M}, perhaps
B) only send the title of single permutation function Fi.
Options a) allows unwarranted third party to intercept and capture constant series, the equipment of the training sequence of the digital data stream that therefore will comprising decodes sends.Yet the advantage of this method is the memory space of saving at transmitting terminal and these two ends of receiving terminal, because only need put into intermediate store for the effective constant series of current transmission, and can delete said constant series when transmission ending.
Options b) prerequisite is, at transmitting terminal and these two ends of receiving terminal, must permanently store all possible permutation function F
1, F
2... F
L(L: integer), just can call and transmit effective permutation function F hereto
iThe advantage of this modification is that unwarranted third party can not determine by used permutation function F
iThe code G that implies
iSequence because its does not also send.
One group of Gi of decoding figure comprises the code g of H quadrature
1, g
2... g
H, they can change training sequence.Thus, among H the orthogonal code v each all can be constituted a vector with P element.Constant H and P are integers.The step of determining one group of Gi of encrypted code in step 220 can be by any one replacement in the following steps:
C) send specific each orthogonal code g according to vector form
1, g
2..., perhaps
D) send the title of the orthogonal code that will use.
Options c) with d) with respect to options a) with b) relevant permutation function F
iThe merits and demerits of determining be that the transmission of customizing messages will reduce the protection that defence is intercepted and captured, and in the storage of transmitting terminal and this two ends predetermined code of receiving terminal with call and will take memory space.
In step 230, hop interval I
HopDetermine mean:
E) stipulated a circulating continuancing time I
Hop, that is, and effective duration, for example 5 milliseconds, perhaps
F) the number Q of specified data grouping, for example number of 3 * data symbol u.
After the encryption key transmission, at step 300 beginning dynamic decoder.First replacement process 400 as described below.In step 410, n is set at " 1 " at interval, and uses from being positioned at permutation function F
iThe group G of some p-I
iCode.In step 420, wait for hop interval I
HopExpire.Be used for determining the time measurement of circulating continuancing time end, perhaps the counting of the packet of Fa Songing is to utilize suitable equipment to finish as counter or trigger.Reach hop interval I when
HopTerminal the time, step 430 at interval n increase numerical value 1.In step 440, whether the currency of comparison interval n is greater than the element sum M of permutation vector.If result relatively is a "Yes", then circulate in step 410 and begin again, and n resets to numerical value " 1 " at interval.If comparative result is a "No", then step 450 is called instantaneous decoding code v
n, said decoding code v
nBe positioned at permutation function F
iN position p-n, that is, and v
n=g
(p-n), and said decoding code v
nApply continuously, until in the cyclic process of step 420, reach hop interval I
HopTerminal the time till, after this, step 430 at interval n increase numerical value " 1 ".
Fig. 6 represents a pond p-1 encrypted code.The first son group of drawing with dotted line comprises for example gets up 4 elements these 4 element combinations, forms two possible group G
iStrictly only occur once if suppose each element, then always have 24 options.The second son group that goes out with the worry line drawing comprises 5 elements.Express two options again for encrypted code, repeatedly modification may take place comprising single code.
Claims (12)
1, a kind of encryption method that is used for digital transmission system, digital data stream wherein (x (t)) comprises an alternate sequence of training sequence or pilot frequency carrier wave and data symbol (u), send said training sequence according to coding form, it is characterized in that: the coding of training sequence is to utilize dynamic encryption code (v
n) realize.
2, method according to claim 1 is characterized in that: dynamic encryption code (v
n) produce by random generator.
3, method according to claim 1 and 2 is characterized in that: said encryption method is used a definite group (G from encrypted code
i) each continuous element (v
n, v
N+1...).
4, method according to claim 3 is characterized in that: the form according to circulation realizes dynamic training sequence (g
1, g
2) said group of (G
i), that is, from start to end, and then ground is from beginning.
5, a kind of coding/decoding method, said method is used for the digital data stream (x (t)) by scanner foundation, an and alternate sequence that comprises training sequence and data symbol (u), wherein training sequence or pilot frequency carrier wave are encoded, and after digital data stream (x (the t)) scanning that receives, from said digital data stream, extract and send it to a correlator, wherein the decoding code (v of receiving terminal
n) also sending to correlator, correlator is sought a maximum according to these two signals, and this maximum is characterized in that as the time of scanner and the correcting variable of frequency correction: the decoding code is dynamic, and code generator produces dynamic decoder code (v
n), as the function of encryption key (200).
6, coding/decoding method according to claim 5 is characterized in that: permutation function (F
i) determine one group of decoding code (v
n) content.
7, according to claim 5 or the described coding/decoding method of claim 6, it is characterized in that following step:
Send an encryption key (200) and thus:
Determine a permutation function (F
i) (210);
Determine one group of decoding code (g
1, g
2... g
H) (220);
Determine a hop interval (I
Hop) (230);
Wherein: these three steps can be carried out according to any order at last.
8, according to any one described coding/decoding method among the claim 5-7, it is characterized in that:, carry out a replacement process (400), comprising circulation with following step:
An interval (n) is set at 1 (410);
Wait for predetermined hop interval (I
Hop) end (420);
(n) increases numerical value 1 (430) at interval;
Carry out following comparison (440): whether the currency of (n) is greater than at permutation function (F at interval
i) sum (M) of interior element, permutation function represents to be used for the dynamic code (g of decoded digital data flow (x (t))
n) the position;
Wherein:, then carry out if result relatively is positive:
(n) resets to numerical value 1 at interval;
Perhaps, if result relatively bears, then:
Make current decoding functions (v
n) with by permutation function (F
i) the decoding code (g of position (p_n) of regulation
P_n) equate.
9, a kind of equipment that is used for the digital data stream of synchronous receiver and reception, wherein:, from the digital data stream that receives, extract training sequence or pilot frequency carrier wave (v in order to realize synchronously
n), and will make it relevant with the decoding code, it is characterized in that: synchronizer is equipped with a dynamic code generator.
10, synchronizer according to claim 9 is characterized in that: said equipment configuration is used for the device of storage encryption key (200).
11, a kind of digital transmission system, it has the synchronous device of digital data stream that is used for receiver and is received, and it is characterized in that receiver is equipped with:
Be used to extract the device of training sequence;
The device that is used for the correcting variable of definite scanner;
Be used to produce the device of dynamic code.
12, a kind of application of encryption method and/or coding/decoding method, digital data stream wherein comprise an alternate sequence of training sequence or pilot frequency carrier wave and data symbol, and training sequence or pilot frequency carrier wave are dynamic codings in wired or wireless network.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP03102524.0 | 2003-08-13 | ||
| EP03102524 | 2003-08-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1836415A true CN1836415A (en) | 2006-09-20 |
Family
ID=34178563
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2004800232291A Pending CN1836415A (en) | 2003-08-13 | 2004-08-03 | Encryption method and decoding method for a digital transmission system |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US20060291656A1 (en) |
| EP (1) | EP1658710A1 (en) |
| JP (1) | JP2007502568A (en) |
| KR (1) | KR20060073598A (en) |
| CN (1) | CN1836415A (en) |
| WO (1) | WO2005018185A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011020445A1 (en) * | 2009-08-21 | 2011-02-24 | 中兴通讯股份有限公司 | Interaction method and apparatus for secure information |
| CN101340437B (en) * | 2008-08-19 | 2011-05-18 | 北京飞天诚信科技有限公司 | Time source regulating method and system |
| CN105721151A (en) * | 2016-04-06 | 2016-06-29 | 北京瀚诺半导体科技有限公司 | Information encryption method in OFDM communication system |
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| EP1880480B1 (en) * | 2005-05-13 | 2016-02-03 | Dspace Pty Ltd | Method and system for communicating information in a digital signal |
| AU2006246322B2 (en) * | 2005-05-13 | 2010-04-22 | Dspace Pty Ltd | Method and system for communicating information in a digital signal |
| JP4662040B2 (en) * | 2005-07-08 | 2011-03-30 | 日本電気株式会社 | Communication system and synchronization control method thereof |
| WO2008072292A1 (en) * | 2006-12-08 | 2008-06-19 | Fujitsu Limited | Mobile communication system, mobile unit and wireless control apparatus |
| US8305999B2 (en) * | 2007-01-05 | 2012-11-06 | Ravi Palanki | Resource allocation and mapping in a wireless communication system |
| KR100842042B1 (en) * | 2007-07-16 | 2008-06-30 | 충남대학교산학협력단 | A method for code-blocks encryption which enables dynamic decryption of encrypted executable code |
| KR102026898B1 (en) * | 2012-06-26 | 2019-09-30 | 삼성전자주식회사 | Method and apparatus for secure communication between transmitter and receiver, method and apparatus for determining the secure information |
| WO2018160223A1 (en) * | 2017-02-28 | 2018-09-07 | Intel IP Corporation | Apparatus, system and method of multi user ranging measurement |
| US11227087B1 (en) * | 2019-01-04 | 2022-01-18 | Cadence Design Systems, Inc. | System, method, and computer program product for distributed learning in an electronic design |
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2004
- 2004-08-03 WO PCT/IB2004/051378 patent/WO2005018185A1/en not_active Application Discontinuation
- 2004-08-03 EP EP04744726A patent/EP1658710A1/en not_active Withdrawn
- 2004-08-03 CN CNA2004800232291A patent/CN1836415A/en active Pending
- 2004-08-03 US US10/567,840 patent/US20060291656A1/en not_active Abandoned
- 2004-08-03 JP JP2006523096A patent/JP2007502568A/en active Pending
- 2004-08-03 KR KR1020067002961A patent/KR20060073598A/en not_active Application Discontinuation
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101340437B (en) * | 2008-08-19 | 2011-05-18 | 北京飞天诚信科技有限公司 | Time source regulating method and system |
| WO2011020445A1 (en) * | 2009-08-21 | 2011-02-24 | 中兴通讯股份有限公司 | Interaction method and apparatus for secure information |
| CN101998388B (en) * | 2009-08-21 | 2015-05-20 | 中兴通讯股份有限公司 | Interaction method and device for security information |
| CN105721151A (en) * | 2016-04-06 | 2016-06-29 | 北京瀚诺半导体科技有限公司 | Information encryption method in OFDM communication system |
Also Published As
| Publication number | Publication date |
|---|---|
| EP1658710A1 (en) | 2006-05-24 |
| US20060291656A1 (en) | 2006-12-28 |
| KR20060073598A (en) | 2006-06-28 |
| JP2007502568A (en) | 2007-02-08 |
| WO2005018185A1 (en) | 2005-02-24 |
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